This application claims the priority of German Application 19734364.3 filed Aug. 8, 1997, the subject matter of which is incorporated herein by reference.
The invention relates to improvements in methods of and in apparatus for conditioning tobacco. More particularly, the invention relates to improvements in methods of and in apparatus for applying to tobacco particles a conditioning agent. Still more particularly, the invention relates to improvements in methods of and in apparatus for intimately contacting moist tobacco particles with water, steam, vapor and/or other suitable fluid conditioning medium, especially for the purpose of causing the tobacco particles to swell, i.e., to increase the specific volumes of such particles.
It is well known to subject comminuted tobacco ribs and/or comminuted tobacco leaf laminae to a variety of treatments which involve contacting the comminuted ribs and/or leaf laminae (hereinafter called tobacco particles) with a fluid medium. Such particles are thereupon converted into rod-like fillers of cigarettes or other rod-shaped smokers"" products; alternatively, the treatment can merely involve a single stage of a composite treatment which can further involve one or more steps prior to and/or subsequent to an increase of the specific volume of the particles.
Manufacturers of cigarettes and/or other rod-shaped articles of the tobacco processing industry are particularly interested in ensuring a pronounced increase of the so-called filling power of tobacco, i.e., in a pronounced increase of specific volume, because this ensures that the articles exhibit a pronounced resistance to deformation without any, or any undue, increase in the quantity of tobacco particles. A heretofore known procedure involves the steps of moistening the particles, thereafter contacting the moistened particles with water vapors, and subsequently drying the moistened and vapor-treated particles.
An object of the invention is to provide a novel and improved method of effectively, predictably and reliably increasing the specific volume of particulate smokable material.
Another object of the invention is to provide a novel and improved method of treating moisturized tobacco particles.
A further object of the invention is to provide a reliable method of increasing the volumes of large quantities of tobacco particles per unit of time.
An additional object of the invention is to optimize the treatment of tobacco particles subsequent to moisturizing and prior to drying.
Still another object of the invention is to provide a novel and improved apparatus for the practice of the above-outlined method.
A further object of the invention is to provide a simple, compact, inexpensive, reliable and versatile apparatus for increasing the specific volumes of comminuted tobacco ribs and/or comminuted tobacco leaf laminae.
Another object of the invention is to provide the above outlined apparatus with novel and improved means for conveying comminuted tobacco leaves through a series of conditioning stations.
An additional object of the invention is to provide the above outlined apparatus with a novel and improved system for the establishment of intimate contact between a fluid conditioning medium and tobacco particles with attendant pronounced swelling of the thus treated particles.
Still another object of the invention is to provide a production line which embodies one or more tobacco conditioning apparatus of the above outlined character.
A further object of the invention is to provide the above outlined apparatus with a plurality of conditioning units which can be designed to contact moisturized tobacco particles with one and the same fluid conditioning medium or with a plurality of different conditioning media.
Another object of the invention is to provide rod-shaped smokers"" products containing rod-like fillers of tobacco particles which have undergone a conditioning treatment in accordance with the above outlined method and/or in the above outlined conditioning apparatus.
An additional object of the invention is to provide the above outlined apparatus with a novel and improved system for simultaneously subjecting tobacco particles to a plurality of treatments, particularly for contacting tobacco particles with a moisturizing medium and simultaneously agitating the particles in at least one novel and improved manner.
One feature of the instant invention resides in the provision of a method of intimately contacting moist tobacco particles with a fluid conditioning medium. The improved method comprises the steps of establishing a preferably essentially gravitational downward flow of moist tobacco particles along a predetermined path, and inducing at least one substantially circular flow of the conditioning medium in a selected portion of the predetermined path so that the tobacco particles traverse and are contacted by conditioning medium in the substantially circular flow.
The at least one circular flow is preferably set up in such a way that it contains an orbiting curtain of conditioning medium.
The inducing step can comprise conveying a stream of a suitable conditioning medium (e.g., steam) along a second path at least substantially transversely of and at least partially across the selected portion of the predetermined path for tobacco particles, discharging streamlets or jets (hereinafter called jets) of conditioning medium from and at least substantially radially of the second path, and orbiting the jets about the second path in the preselected portion of the predetermined path.
Steam is one of presently preferred conditioning media; the purpose of the conditioning medium or media is to effect an increase of the specific volume of tobacco particles which traverse the selected portion of the predetermined path.
Still further, the method can comprise the step of moisturizing the particles of tobacco in a second portion of the predetermined path upstream of (i.e., normally at a level above) the preselected portion of such predetermined path.
The method can also comprise the step of reducing the moisture content of tobacco particles in a further portion of the predetermined path subsequent to contacting of the particles with the conditioning medium in the selected portion of the predetermined path. Otherwise stated, such additional step can involve drying of the tobacco particles subsequent to traversal by the particles of the selected portion of the predetermined path.
A presently preferred inducing step includes supplying the conditioning medium into the selected portion of the predetermined path in the form of an array of jets containing atomized or essentially atomized conditioning medium and issuing substantially radially from a source extending transversely of and across the selected portion of the predetermined path, and orbiting the jets around the source.
Still further, the inducing step can include establishing a plurality of at least substantially circular flows of atomized conditioning medium in successive selected portions of the predetermined path, e.g., in two successive selected portions one of which is or can be located at a level above the other selected portion. The establishing step can comprise confining tobacco particles to a movement substantially vertically downwardly through the selected portion of the predetermined path. As used herein, the term xe2x80x9csubstantially vertically downwardlyxe2x80x9d can involve any movement which has a vertical component or is exactly vertical.
Another feature of the invention resides in the provision of an apparatus for contacting moist tobacco particles with a fluid conditioning medium. The apparatus comprises a first conveyor defining a predetermined path for an essentially gravitational downward flow of tobacco particles, and at least one second conveyor for a stream of conditioning medium. The at least one second conveyor is arranged to establish a second path extending at least substantially transversely of a selected portion of the predetermined path and having orifices arranged to discharge jets of conditioning medium substantially radially outwardly from the second path and to orbit the jets around the second path in the selected portion of the predetermined path.
The at least one second conveyor can comprise an elongated conduit having a substantially horizontal axis and being driven to rotate about such axis.
As already mentioned above, the conditioning medium contains or should contain a fluid which effects a swelling (i.e., an increase of specific volume) of tobacco particles in the selected portion of the predetermined path.
The at least one second conveyor can comprise, or can cooperate with, means for mechanically propelling tobacco particles to orbit about the second path in the selected portion of the predetermined path. This establishes a longer-lasting contact between tobacco particles and the atomized conditioning medium. If the second conveyor comprises an elongated conduit having a substantially horizontal axis and being driven to rotate about such axis, the means for mechanically propelling tobacco particles can comprise impellers (e.g., in the form of straight or substantially straight elongated pins or needles) extending from and substantially radially of the conduit.
The first conveyor can be provided with an inlet for the admission of tobacco particles into the predetermined path, and the apparatus can further comprise means for contacting tobacco particles with a moisturizing agent at the inlet of the first conveyor. The moisturizing agent can contain water, and the means for contacting tobacco particles with such moisturizing agent can include at least one nozzle arranged to discharge moisturizing agent (e.g., an atomized agent) into the inlet so that the particles can be influenced by such moisturizing agent before they enter the range of the conditioning medium in the single or in the first or foremost selected portion of the predetermined path.
The apparatus can further comprise means for advancing tobacco particles into the inlet of the first conveyor or from such inlet into the selected portion of the first path; the advancing means can comprise a driven rotary cell wheel which is provided in or adjacent the first conveyor, particularly at the inlet of the first conveyor.
Still further, the improved apparatus can comprise a tobacco dryer which is provided at an outlet of the first conveyor, for example, at the lower end of a substantially upright duct which constitutes or forms part of the first conveyor.
The apparatus can comprise a plurality of second conveyors which can be disposed one below the other in discrete selected portions off the predetermined path. The second conveyors may but need not be at least substantially identical. For example, at least one of two or more second conveyors can comprise means for mechanically propelling tobacco particles to orbit about the respective second path in the corresponding selected portion of the predetermined path.
The inlet of the first conveyor can be disposed at a level above the only or above the topmost second conveyor, and the outlet of the first conveyor can be located at a level below the only or below the lowermost second conveyor.
A further feature of the invention resides in the provision of a conditioning unit for a flow of tobacco particles which are confined to an advancement along a predetermined path. The conditioning unit comprises a rotary tubular conveyor for a stream of a fluid conditioning medium. The conveyor extends at least substantially transversely of a selected portion of the predetermined path for tobacco particles and has a plurality of orifices arranged to discharge orbiting biting jets of conditioning medium from the stream into the tobacco particles in the selected portion of the predetermined path.
The conduit can be provided with external mechanical impellers for orbiting tobacco particles about the conduit in the selected portion of the predetermined path.
The conditioning medium can contain or can consist of steam, and the improved conditioning unit further comprises means for connecting the conduit with a source of the selected conditioning medium or media. The conditioning medium can also contain or consist of water; the conduit is then connected to a suitable source of water which is used as, or as a part of, the conditioning medium.
Still further, the conditioning unit can comprise or cooperate with means for treating tobacco particles in the predetermined path at a level above the selected portion of such path; the tobacco treating means can comprise means for moisturizing tobacco particles at an inlet of the predetermined path.
Last but not least, the improved conditioning unit can comprise means for conditioning tobacco particles in the predetermined path at a level at least partially below the selected portion of such path; the conditioning can involve renewed contacting of tobacco particles with steam or the like to further increase the specific volume of treated tobacco, or another type of treatment (e.g., drying at the outlet of the predetermined path).
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved conditioning apparatus itself, however, both as to its construction and the mode of assembling and/or operating the same, together with numerous additional important features, advantages and attributes thereof, will be best understood upon perusal of the following detailed description of certain presently preferred specific embodiments with reference to the accompanying drawings.